1. Field of Use
The present invention is in the field of medical devices which deliver radio-frequency energy to cut tissue. More specifically, the invention is in the field of cutting probes for arthroscopic surgery.
2. Background
Arthroscopic surgery is becoming increasingly popular, because it generally does less damage than open procedures, produces less scarring in and around joints, and results in faster healing and return of the patient to full productivity.
Nevertheless, arthroscopic surgery has its limitations. The surgeon must operate through a narrow tube, which is awkward. Only one probe can be used at a time. Often the viewing camera is positioned at an angle different from the surgeon""s normal gaze. This contrasts with xe2x80x9copen surgeryxe2x80x9d where the surgeon has relative ease of viewing the surgical site and can freely move both hands, even utilizing the hands of colleagues.
In view of such difficulties of arthroscopic surgery, it is understandable that laser, microwave and radio-frequency (RF) probes which simultaneously cut and coagulate are preferred. However, current probes are poorly adapted to certain activities, such as cutting narrow tendons or ligaments. Current probes have convex, pointed and/or flat tips. U.S. Pat. No. 5,308,311, issued May 3, 1994 to Eggers and Shaw, is exemplary in that it discloses a laser probe with a pointed tip and convex, side. With current probes, the surgeon has little control when pressing against a tough ligament. Now as the surgeon cuts through one portion of the ligament, the probe slips out of position. The surgeon must reapproximate the probe and cut again, an inefficient process. And, unless the surgeon is able to stop pressure at exactly the right time, the probe may slip and cut an adjacent structure. Because the surgeon must repeatedly reapproximate and cut the ligament, the surgeon has difficulty in cleanly ablating the ligament or tendon. Thus, there are certain procedures that surgeons still prefer to perform in the xe2x80x9copen.xe2x80x9d Unfortunately, this often results in bigger scars, longer convalescence, and more irritation of an already irritated joint.
What is needed is a probe that can simultaneously direct the tendon to the energy source (e.g., RF) and apply RF to cleanly and smoothly ablate the tendon or ligament. The advantage is that some procedures that have been considered too awkward or difficult to perform by arthroscopy can now be performed more effectively by arthroscopy.
A thermal energy delivery apparatus is disclosed which has a probe means including a distal end and a proximal end, wherein the distal end has a concave tip. A first electrode means is also positioned at the distal end of the probe means, so that the first electrode means is configured to deliver sufficient thermal energy to cut ligaments or tendons. The thermal energy delivery apparatus also includes a cabling means coupled to the proximal end of the probe means. The cabling means can be either permanently or impermanently coupled to the probe means.
In another embodiment, there is an RF probe comprising a distal tip, wherein the distal tip has a concave curve and an electrode, whereby the concave curve on the distal tip helps constrain tissue for cutting. In another embodiment, the RF probe has a concave curve with a sharp edge. In yet another embodiment, the RF probe has a concave curve separated from the lateral edges of the RF probe.
Another embodiment of this invention is a method of cutting a ligament or tendon by (a) providing an RF probe with a distal tip with a concave curve; (b) approximating the RF probe to the ligament or tendon to be cut; and (c) applying RF energy through the curve, thereby cutting the ligament, tendon, or other tissue.
In another embodiment of the invention a controller for controlling the delivery of energy and liquid to a surgical instrument with a temperature sensor is disclosed. The energy is supplied by an energy source and the liquid is supplied by a pump. The controller includes a temperature and a flow regulator. The temperature regulator is coupled to the energy source and coupled to the pump. The temperature regulator is responsive to a first temperature indication from the temperature sensor to determine that the first temperature indication exceeds a setpoint and to reduce an energy level from the energy source. The flow regulator is coupled to the pump and coupled to the temperature regulator. The flow regulator includes responsiveness to the first temperature indication to increase a flow of the liquid from the pump.